The present invention relates to implantable medical devices and associated pump devices for infusing a fluid into a body, and the methods and construction of such devices. Additionally, the present invention concerns the means by which an implantable pump or an implantable medical device measures the amount of fluid contained within the pump.
The use of implantable fluid medication dispensers is presently well known in the art. Examples of implantable fluid medication dispensers are contained within U.S. Pat. Nos. 5,328,460, 5,443,450 and 5,643,207. Such dispensers, for example, are used to dispense a specified amount of medication into a patient""s body, such as, for example, providing for the delivery of low doses of morphine into a patient""s body in an effort to treat cancer pain.
Implantable fluid medication dispensers typically include an internal fluid medication reservoir for receiving, storing and dispensing a supply of a fluid medication. This reservoir is generally included within a housing of some shape or form that may easily be implantable into the body. Other components of the devices include a power source (such as a battery), a mechanism for pumping the fluid medication into the patient""s body and a programmable mechanism to assist in dispensing the fluid medication according to a predetermined schedule.
Because these fluid medication dispensers are implanted within a patient""s body, which allow them to be portable, they sometimes must be replenished with medication. As a result, the implantable fluid medication dispensers may also include some means to replenish the fluid medication within the reservoir. For reference, please refer to the disclosure of U.S. Pat. No. 5,443,450 to Kratoska, et al. for a discussion of typical reservoir refill assemblies (Column 1, Lines 26-37). Unfortunately, determining the level of mediation contained within the fluid medication dispensers, using a more accurate and less intrusive manner, has, in the past, proved to be problematic. At present, the lack of a fluid medication being dispensed to the patient is generally detected by physiological measures. Such measures, for example, may include symptoms associated with the malady to which the fluid medication is directed to prevent or abate.
There exists, therefore, a significant need for improvement in the measuring abilities of such implantable medication dispensers. Instead of relying upon symptomatic factors, which may cause unwarranted pain to the patient, to determine when an implantable fluid medication device is in need of a replenishment of fluid, it would be desirable to provide a means to determine the amount of fluid remaining in another manner. The present invention fulfills these needs and provides further advantages.
Disclosures relating to implantable medication dispensers include the U.S. Patents listed below in Table 1.
As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, at least some of the devices and methods disclosed in the Patents contained within Table 1 may be modified advantageously in accordance with the teachings of the present invention.
The present invention overcomes at least some of the disadvantages of the prior art by providing a method of and apparatus for measuring the level of a fluid medication within an implantable pump apparatus and fluid medication dispenser, and by providing an improved structure respecting same.
The present invention has certain objects. That is, the present invention provides solutions to at least some of the problems existing in the prior art respecting the measurement of the amount of fluid remaining in an implantable medication dispenser, including the difficulties encountered in prior devices respecting:
(a) providing an accurate measurement of the amount of fluid medication remaining within an implantable pump apparatus;
(b) providing an accurate, reliable diagnosis concerning the amount of fluid medication remaining within the implantable pump apparatus without relying on physiological factors or symptoms of the patient;
(c) providing a safe and nonintrusive means to measure the amount of fluid medication remaining within the implantable pump apparatus without causing harm to the patient;
(d) basing the requirement of additional fluid medication on the detection of physiological factors;
(e) basing the requirement of additional fluid medication on a patient""s symptoms; and
(f) basing the requirement of additional fluid medication on other inaccurate and potentially unsafe methods.
The present invention provides solutions to at least some of the foregoing problems.
The present invention provides solutions to at least some of the problems associated with known implantable fluid medication dispensers.
Some embodiments of the present invention provide certain advantages including one or more of:
(a) accurately indicating the amount of fluid remaining within an implantable fluid medication dispenser;
(b) safely measuring the amount of fluid remaining within an implantable fluid medication dispenser;
(c) measuring the amount of fluid remaining within an implantable fluid medication dispenser without relying on physiological factors of the patient;
(d) measuring the amount of fluid remaining within an implantable fluid medication dispenser without relying on the symptoms of the patient; and
(e) measuring the amount of fluid remaining within an implantable fluid medication dispenser without relying on other inaccurate and potentially unsafe methods.
Some embodiments of the present invention have certain features relating to the measurement of the amount of a fluid medication contained within an implantable fluid medication dispenser, including one or more of:
(a) an expandable reservoir for receiving a specified amount of a fluid medication within an enclosure;
(b) a first conductor operably attached to the first end of the expandable fluid reservoir member; and
(c) a second conductor operably attached to the second end of the expandable fluid reservoir member.